Epidemiology of severe influenza outcomes among adult patients with obesity in Detroit,Michigan, 2011

We conducted a retrospective cohort study to evaluate the impact of obesity on influenza disease severity. Individuals with obesity were more likely to have lower pulmonary disease manifestations [OR = 1·97 (95% CI 1·05, 3·69), P = 0·03] and to be admitted to an inpatient ward [OR = 2·93 (95% CI 1·50, 5·71), P = 0·002] when compared with non‐obese individuals. Among admitted individuals, persons with obesity were more likely to require a lengthy hospital stay [OR = 3·86 (95% CI 1·03, 14·42), P = 0·045]. Five of the six deaths in study subjects occurred in persons with obesity.     

Association between human recombinant EPO and peripheral vascular disease in diabetic patients receiving peritoneal dialysis

Peripheral vascular disease is a serious and frequent problem in diabetic patients. Since the beginning of the widespread use of erythropoietin (EPO), we have noted an increase in peripheral vascular disease in diabetic patients receiving peritoneal dialysis and erythropoietin. This prompted us to study the effects of erythropoietin on peripheral vascular disease in patients receiving peritoneal dialysis. We retrospectively reviewed medical records of all diabetic patients in our program who received peritoneal dialysis from 1990 to 1996. Demographic and laboratory data as well as EPO use data were collected. Hospital days and occurrence of vascular events (defined as peripheral vascular surgery, amputation, or recommendation of vascular surgery or amputation by a vascular surgeon) were determined for diabetic patients receiving peritoneal dialysis. Comparisons were made between those who received EPO and those who did not received EPO, as well as comparing vascular events in 28 patients who received peritoneal dialysis before and after beginning EPO. Patients who received erythropoietin were found to have a significantly shorter time to a first vascular event, a greater number of vascular events, and more hospital days associated with vascular disease than diabetic patients who did not receive erythropoietin. With multivariate analysis, significant risk factors for the development of peripheral vascular disease in these patients were erythropoietin use, erythropoietin dose, and smoking. Twenty-eight patients who initially performed peritoneal dialysis without receiving EPO, and later received EPO, had a significant increase in vascular events, including amputations only while receiving EPO. We found the use of erythropoietin to be associated with peripheral vascular events in diabetic patients who receive peritoneal dialysis. Further investigation is warranted.     

A randomized prospective comparison of oral versus intraperitoneal ofloxacin as the primary treatment of CAPD peritonitis

Summary: Oral ofloxacin has been successfully used in our centres for the primary treatment of peritonitis complicating continous ambulatory peritoneal dialysis (CAPD). In view of the progressive rise in the resistance rate to ofloxacin among peritoneal bacterial isolates, a study was conducted to determine if oral ofloxacin remains a viable first line treatment for CAPD peritonitis in our centres and if the result can be improved by changing from an oral to an intraperitoneal (i.p.) route. In patients on three 2 L daily CAPD exchanges, ofloxacin given at the i.p. dosage of 200 mg loading followed by 25 mg/L of peritoneal dialysate achieved overnight trough peritoneal levels which are at least four times the minimal 90% inhibitory concentration (MIC90) of most bacterial pathogens without significant accumulation in the systemic circulation. This i.p. dosage was therefore chosen for the clinical study and the result was compared to that using ofloxacin given in the oral dosage of 400 mg loading followed by 300 mg once daily as maintenance. of all the recruited episodes, 35 were eligible for analysis. the overall primary cure rate including primary failures and relapses was 55.6% (10/18) in the oral treatment group and 70.6% (12/17) in the i.p. treatment group. the corresponding figures for gram positive bacterial (g +) infections were 36.4% and 50%, for gram negative bacterial (g -) infections were 66.7 and 80% and for culture negative infections were 75 and 80%. In culture positive cases, all treatment failures were due to resistant infections which were observed in 42.3% of all bacterial isolates, 47.1% of g + isolates and 33.3% of g - isolates. Due to the high background level of bacterial resistance among our CAPD population, ofloxacin monotherapy given either by the oral or the i.p. route can no longer be recommended for the primary treatment of CAPD peritonitis.     

Panel discussion review: session two--interpretation of observed associations between multiple ambient air pollutants and health effects in epidemiologic analyses

Air pollution epidemiologic research has often utilized ambient air concentrations measured from centrally located monitors as a surrogate measure of exposure to these pollutants. Associations between these ambient concentrations and health outcomes such as lung function, hospital admissions, and mortality have been examined in short- and long-term cohort studies as well as in time-series and case-crossover studies. The issues related to interpreting the observed associations of ambient air pollutants with health outcomes were discussed at the US EPA sponsored workshop on December 13 and 14, 2006 in Chapel Hill, North Carolina, USA. The second session of this workshop focused on the following topics: (1) statistical methodology and study designs that may improve understanding of multipollutant health effects; (2) ambient concentrations as surrogate measures of pollutant mixtures; and (3) source-focused epidemiologic research. New methodology and approaches to better distinguish the effects of individual pollutants include multicity hierarchical modeling and the use of case-crossover analysis to control for copollutants. An alternative approach is to examine the mixture as a whole using principal component analysis. Another important consideration is to what extent the observed health associations are attributable to individual pollutants, which are often from common sources and are correlated, versus the pollutant mixtures that the pollutants are representing. For example, several ambient air concentrations, such as particulate matter mass, nitrogen dioxide, and carbon monoxide, may be serving as surrogate measures of motor vehicle exhaust. Source apportionment analysis is one method that may allow further advancement in understanding the source components that contribute to multipollutant health effects.     

The viscosity and viscoelasticity of blood in small diameter tubes.

Both steady and oscillatory flow of blood are studied in small rigid tubes having radii from 0.02 to 0.2 cm. This is done for rates of flow extending from higher values where nonlinear effects are evident down to very low values where the pressure to flow relations are linear. The data are analyzed using the parameters of Poiseuille theory for steady tube flow and of the linear, viscoelastic theory for oscillatory tube flow. In the low flow, linear region the apparent values of the steady flow viscosity and the oscillatory flow viscosity at 2 Hz are dependent upon the tube radius, this being in contraction with the assumptions of the theories. Another theoretical analysis is then made assuming that the blood in a boundary zone at the tube wall has modified viscous and viscoelastic properties. The measurements are in good agreement with this analysis. For low rates of flow, the steady flow is pluglike, the blood in the core moving as a solid. The pressure to flow relation is then controlled by the boundary zone for all tube radii. In this case of oscillatory flow, the core undergoes viscoelastic deformation and thus flow occurs in both the core and the boundary zone. For larger tubes, the boundary zone effects became insignificant. Under this condition the oscillatory pressure to flow relation may be used to obtain the viscoelasticity of the blood, free from the boundary layer artifacts which dominate the steady flow.